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Saturday, 13 August 2011

27. 3ds Max Quicktip: MassFX and complex Sims

Hi All

By now you’ve probably had a little play with MassFX and seen the reliability, performance and stability it offers in 3ds Max 2012. It currently only supports Rigid Body simulations. This is typically what most people perform when calculating dynamic simulations, so it made sense to focus on this first. However, you might have stumbled when trying to calculate a simulation on an object which has a complex form, or contains some open areas. For instance, dropping some flowers into a vase.

Lets look at the steps:

1. In this very simplified example, we have the below setup:

Green Teapot = to be dropped into blue teapot = dynamic object

Blue Teapot = Container = Static object.

Creme Box = Static object

2. Now select each object and apply the relevant rigid body type individually.

Green Teapot = Set as Dynamic

Blue Teapot + Creme Box = Static

You do this via the highlighted button above. Left-click and hold to see the flyout. Don’t worry if you choose the wrong type you can quickly change this via the modifier applied to the object. (Showing the flexibility of this toolset.)

Dynamic = no underlying keyframes, use MassFX to make sim

Kinematic = use applied keyframe animation

Static = do not move, but form part of sim

3. From here, perform a quick test, using the playback option highlighted below. You will see that this works directly in the viewport, with all the new viewport lighting, materials, and AO updating interactively.

You should see the teapot bounce off or float, where the lid used to be. This is due to capping of the simulation cage. Once complete, ensure you use the same ‘playback’ option to Stop the simulation. Do not use 3ds Max’s standard animation timelines at the bottom of the screen. You are currently not working with animation data, but instead performing simulations, therefore the two are currently disconnected.

4. To solve this we need to change the ‘Mesh Type’ option in the modifier of the relevant object. Select the container object (Blue Teapot in this case) and navigate to the modifier tab of the command panel. Then scroll until you see the below highlighted option. (Found in the ‘Physical Meshes’ group)

Change the Mesh Type option from Convex to Composite. From there, now press the ‘Generate button.’ This, in essence generates a collision plane for each face of the object. You can tweak the settings to customise for your requirements.

Notice what happens to the ‘blue cage’ of the object in the viewport.

5. Now re-run the simulation, and notice the how the object will now fall inside the container.

Below shows the difference, how changing this simple default settings make when working on more complex scenes.

A: Using Convex Mesh Type

B: Using Composite Mesh Type

I would also recommend to not just use this toolset for animations or dynamics, but also use it extensively when you need to set up simple, but time consuming scenes. As an example, I will use this tool when I want to place some cutlery into a drainer/container next to a sink. I can of course do this manually, but on render time, I may have some intersecting objects. So its far easier to just drop them into the container in a few seconds, rather than spend 10-20 minutes placing them individually. This toolset should be used for more than just the typical ‘destroying stuff.’ It’s worth noting that this technology is co-developed between Autodesk and NVidia.

As a parting thought, remember, all objects in the scene should have a volume – i.e. no planes!

Comments

27. 3ds Max Quicktip: MassFX and complex Sims

Hi All

By now you’ve probably had a little play with MassFX and seen the reliability, performance and stability it offers in 3ds Max 2012. It currently only supports Rigid Body simulations. This is typically what most people perform when calculating dynamic simulations, so it made sense to focus on this first. However, you might have stumbled when trying to calculate a simulation on an object which has a complex form, or contains some open areas. For instance, dropping some flowers into a vase.